.top{
    width: 780px;
    height: 183px;
    background-color: crimson;
    margin-bottom: 2px;

}
.banner{
    width: 780px;
    height: 150px;
    background: url(../img/banner.jpg);
   


}
.nav{
    width: 780px;
    height: 33px;

}
.nav li{
    width: 78px;
    text-align: center;
    float: left;
    line-height: 33px;
    background: url(../img/button1.jpg);
}
.nav a:hover{
    background: url(../img/button1_bg.jpg);
    display: block;


}